I bought this to layer on during the cold morning runs, and it has become my go to piece for anything outdoors. It was surprisingly warm by itself and rarely needs to be layered with anything. It stays in place (some tops like this ride up) during all my runs and hikes. It is true to size, but be aware that when you use the thumb holes the sleeves get relatively shorter for us tall girls. Layer it with a soft shell on the windy days and you're ready to go!